Several federal screeners have been suspended indefinitely, said Nico Melendez, said a spokesman for the Transportation Security Administration in Washington, D.C.
U.S. Attorney Edward Kubo Jr. said people have been questioned, but there have been no arrests and no charges filed.
''I can confirm an investigation is ongoing into several TSA employees concerning the theft of items from luggage,'' Kubo said.
It is believed the luggage involved belonged to Japanese visitors, but that has not been confirmed, Kubo said.
Kubo also declined to confirm whether four employees were involved, as had been reported.
''It may end up being more, it may end up being less,'' he said.
The federal agency's law enforcement arm is handling the investigation, along with special agents from the Department of Homeland Security Inspector General's Office, Kubo said.
''This was brought to light by TSA screeners,'' said Melendez. ''This re-emphasizes the need for passengers to keep valuables in their carry-on or on their person.''